Patch "scsi: fix memory leak with scsi-mq" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

scsi: fix memory leak with scsi-mq

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
scsi-fix-memory-leak-with-scsi-mq.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Tony Battersby <[email protected]>
Date: Thu, 16 Jul 2015 11:40:41 -0400
Subject: scsi: fix memory leak with scsi-mq

From: Tony Battersby <[email protected]>

commit 0c958ecc69c277b25f38f72bc6d18ab145e8167c upstream.

Fix a memory leak with scsi-mq triggered by commands with large data transfer length.

__sg_alloc_table() sets both table->nents and table->orig_nents to the same value. When the scatterlist is DMA-mapped, table->nents is overwritten with the (possibly smaller) size of the DMA-mapped scatterlist, while table->orig_nents retains the original size of the allocated scatterlist. scsi_free_sgtable() should therefore check orig_nents instead of nents, and all code that initializes sdb->table without calling __sg_alloc_table() should set both nents and orig_nents.

---
 drivers/scsi/scsi_error.c |    2 +-
 drivers/scsi/scsi_lib.c   |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

@@ -944,7 +944,7 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd
 			    scmd->sdb.length);
 		scmd->sdb.table.sgl = &ses->sense_sgl;
 		scmd->sc_data_direction = DMA_FROM_DEVICE;
-		scmd->sdb.table.nents = 1;
+		scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
 		scmd->cmnd[0] = REQUEST_SENSE;
 		scmd->cmnd[4] = scmd->sdb.length;
 		scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);

@@ -583,7 +583,7 @@ static struct scatterlist *scsi_sg_alloc
 
 static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
 {
-	if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS)
+	if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
 		return;
 	__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
 }

@@ -597,8 +597,8 @@ static int scsi_alloc_sgtable(struct scs
 
 	if (mq) {
 		if (nents <= SCSI_MAX_SG_SEGMENTS) {
-			sdb->table.nents = nents;
-			sg_init_table(sdb->table.sgl, sdb->table.nents);
+			sdb->table.nents = sdb->table.orig_nents = nents;
+			sg_init_table(sdb->table.sgl, nents);
 			return 0;
 		}
 		first_chunk = sdb->table.sgl;

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/scsi-fix-memory-leak-with-scsi-mq.patch